Progress 09/01/10 to 08/31/13
Outputs
Target Audience: Vegetable growers; Industry personnel; County and state extension agents; Scientists in plant pathology and other agricultural sciences. Changes/Problems: None. What opportunities for training and professional development has the project provided? Graduate students, postdoctoral students, county extension agents, and vegetable growers were educated and trained in the project for management of vegetable diseases. How have the results been disseminated to communities of interest? Results have been disseminated to stakeholders through local, national and international meetings, publications,and frequent visits of growers, industry representatives, extension agents, and other end users. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
A technique was developed to detect squash fruit infected by Phytophthora capsici before visible symptoms were apparent based on the odor produced by infected fruit. Infected squash fruit produced methoxy-phenyl –oxime, 2-ethyl, 1-hexanol, ethanol, and other volatiles. Parasitic wasps were trained to be a biosensor that could detect a difference between fruit inoculated with P. capsici and non-inoculated fruit one day after inoculation. The biosensor successfully detected P. capsici specifically when used to detect squash fruit inoculated with P. capsici or Pythium sp. A molecular method was also developed based on quantitative real-time polymerase chain reaction analysis that sensitively and specifically detected P. capsici associated with infected fruits and seedlings of cucurbit crops. Sensitivity of P. capsici isolates from different vegetable crops to fungicides was determined, which indicated that the isolates were sensitive to mandipropamid, dimethomorph, and fluopicolide based on mycelial growth, zoospore germination, and sporangial production. The majority of isolates were either resistant or intermediately sensitive to cyazofamid based on mycelial growth or sporangial production, though the isolates were sensitive to this compound based on zoospore germination. A series of experiments were conducted to evaluate the effectiveness of selected fungicides for suppression of different types of propagules of P. capsici in different types of soils. Fluopicolide, mandipropamid, ametoctradin and dimethomorph were effective in disease reduction in different soils under greenhouse conditions when zoospores, oospores, or mycelia of P. capsici were used to inoculate the soils. Repeated field experiments conducted on squash, zucchini, bell pepper, cucumber, and watermelon showed that these fungicides reduced Phytophthora blight significantly. Systemic resistance inducers and soil amendment with biocidal cover crops were evaluated in laboratory, greenhouse, and field studies to develop integrated programs for control of P. capsici. Integrated use of effective fungicides, soil amendment with biocidal cover crops (e.g. mustard), systemic resistance inducers, and resistant cultivars enhanced reduction of Phytophthora blight on vegetables. Results of the studies were presented in national and international meetings and frequent visits of growers, industry representatives, extension agents, and other end users.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Sanogo, S., and Ji, P. 2013. Water management in relation to control of Phytophthora capsici in vegetable crops. Agricultural Water Management 129:113-119.
Jackson, K. L., Yin, J., and Ji, P. 2012. Sensitivity of Phytophthora capsici from vegetable crops in Georgia to mandipropamid, dimethomorph, and cyazofamid. Plant Disease 96:1337-1342.
Sanogo, S., and Ji, P. 2012. Integrated management of Phytophthora capsici on solanaceous and cucurbitaceous crops: current status, gaps in knowledge, and research needs. Canadian Journal of Plant Pathology 34:479-492.
Candole, B. L., Conner, P. J., McGregor, C., Waters, V., and Ji, P. 2012. The disease reactions of heirloom bell pepper California Wonder to Phytophthora capsici. Agricultural Sciences 3:417-424.
Ji, P., Jackson, K. L., Yin, J., Langston, D. B., and Csinos, A. S. 2011. Developing biological and chemical management programs for Phytophthora blight on pepper and cucurbits. Page 18, in: Abstracts of 3rd International Phytophthora capsici Conference. Duck Key, FL.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Quantitative real-time polymerase chain reaction (PCR) techniques were developed for detection and quantification of P. capsici associated with infected fruits and seedlings of cucurbit crops. Specificity of the techniques in response to P. capsici was determined by comparative studies with plants infected by other pathogens. Detection of fruit rot of squash caused by P. capsici using trained parasitic wasps was conducted in repeated studies. It was confirmed that the wasps could detection volatiles emitted from infected squash before appearance of visible symptoms. Studies are on-going to determine the specificity of the wasps in response to P. capsici infection by comparing responses to fruit rot caused by other pathogens including Pythium spp. Isolates of P. capsici were collected from different vegetable crops and potential fungicide resistance development in the pathogen population was continuously monitored. The results indicated that none of the isolates was resistant to fluopicolide, dimethomorph or mandipropamid. Selected systemic resistance inducers and biocidal cover crops were evaluated in integrated programs for control of P. capsici under field conditions. Integrated use of biocidal cover crops (e.g. mustard) as soil amendments and induced systemic resistance enhanced reduction of Phytophthora blight on squash. Results of the studies were presented in regional and national meetings and frequent visits of growers, industry representatives, extension agents, and other end users. PARTICIPANTS: Pingsheng Ji, Assistant Professor, University of Georgia; David B. Langston, Professor, University of Georgia; Alex, S. Csinos, Professor, University of Georgia. TARGET AUDIENCES: Vegetable growers; Industry personnel; County and state extension agents; Scientists in plant pathology, weed science, and other agricultural sciences. PROJECT MODIFICATIONS: None.
Impacts
Phytophthora blight incited by P. capsici has become a serious disease in recent years in the production of cucurbits, peppers, and a variety of other vegetable crops. The disease is extremely damaging in Georgia and other southeastern states. In this project, non-destructive sensing techniques and molecular methods were developed to detect and predict disease development and biorational disease management tactics were developed, which have the promise to significantly improve disease control, reduce fungicide inputs, and increase the sustainability of vegetable industries.
Publications
- Jackson, K. L., Yin, J., Csinos, A. S., Scherm, H., and Ji, P. 2011. Diversity and fungicide resistance of Phytophthora capsici on vegetable crops in Georgia. Phytopathology 101:S79.
- Ji, P., Yin, J., and D. Kone. 2011. Application of acibenzolar-S-methyl and standard fungicides for control of Phytophthora blight on squash. Crop Protection 30:1601-1605.
- Zhang, S., Klassen, W., Mo, X., Ji, P., and Gevens, A. J. 2011. Evaluation of acibenzolar-S-methyl and silicic acid for control of Phytophthora blight caused by Phytophthora capsici in squash. Proc. Fla. State Hort. Soc.124:154-161.
- Zhang, S., Klassen, W., Mo, X., Ji, P., and Gevens, A. J. 2011. Evaluation of acibenzolar-S-methyl and silicic acid for control of Phytophthora blight in squash caused by P. capsici. V5, in: Abstracts of 2011 Meeting of the Florida State Horticulture Society. St. Petersburg, FL.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Volatiles produced by infected squash fruit were analyzed and the identified chemicals included methoxy-phenyl -oxime, 2-ethyl, 1-hexanol, and ethanol, while several more chemicals were apparent but not yet identified. The volatiles emitted from infected squash could be detected by trained parasitic wasps within 1-day of infection and before appearance of visible symptoms. Further studies will be necessary to determine the specificity of the responses of the trained parasitic wasps to P. capsici infection. The effect of soil types on efficacy of new active ingredients of chemical fungicides, including fluopicolide, mandipropamid, ametoctradin and dimethomorph, was evaluated. These chemicals provided significant disease reduction in different types of soils in greenhouse studies. Inoculation of soils with different spores (zoospores and oospores) or mycelia of P. capsici indicated that the compounds were effective in suppression of these propagules. Field studies on bell pepper, cucumber, squash, and watermelon indicated that these products provided significant disease suppression. In addition, two experimental fungicides being evaluated have also shown promising disease control efficacy in lab and field studies. To monitor fungicide resistance development in P. capsici populations, isolates were collected from different vegetables, including bell pepper, squash, zucchini, cucumber, watermelon, and cantaloupe, at different locations in GA. None of the isolates was resistant to 10 or 100 ppm of fluopicolide or mandipropamid, while the majority of the isolates were sensitive to 100 ppm of mefenoxam and all of the isolates were insensitive to 100 ppm of cyazofamid. Repeated field experiments indicated that soil amendments with Brassica cover crops reduced incidence of Phytophthora blight on squash. Results of the studies were presented in regional and national meetings and frequent visits of growers, industry representatives, extension agents, and other end users. PARTICIPANTS: Pingsheng Ji, Assistant Professor, University of Georgia; David B. Langston, Professor, University of Georgia; Alex, S. Csinos, Professor, University of Georgia. TARGET AUDIENCES: Vegetable growers; Industry personnel; County and state extension agents; Scientists in plant pathology, weed science, and other agricultural sciences. PROJECT MODIFICATIONS: None
Impacts
Vegetables are important food and cash crops in Georgia with more than 30 different vegetable crops produced in the state and a farm gate value of more than $900 million. Vegetable production in Georgia is seriously impacted by Phytophthora blight induced by Phytophthora capsici. Studies in this project indicated that effective new chemical fungicides, cultural practices, and early detection of disease development had the promise to be useful components in integrated programs to significantly reduce losses caused by this devastating disease.
Publications
- Ji, P., Kone, D., Yin, J., Jackson, K. L., and Csinos. A. S. 2011. Soil amendments with Brassica cover crops for management of Phytophthora blight on squash. Pest Management Science (DOI: 10.1002/ps.2308).
- Kuhn, P., Babadoost, M., Thomas, D., Ji, P., Mclean, H., Hert, A., Tory, D., Tally, A. 2011. Evaluation of drip applications of Revus in fungicide programs for management of Phytophthora blight (Phytophthora capsici) on bell pepper and squash. Phytopathology 101:S94.
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